A conventional portable biomass stove as disclosed in Chinese Utility Model Patent No. CN203980352U, includes an inner tubular seat and an outer tubular seat. The inner tubular seat has an inner tubular body portion that defines a combustion chamber and that has a plurality of through holes extending radially and communicating fluidly with the combustion chamber. The inner tubular seat further has a seal portion that extends radially outward from a top end of the inner tubular body portion to a top end of the outer tubular seat in a sealing contact manner. The outer tubular seat surrounds the inner tubular body portion, and is formed with a plurality of air inlets that are located under the inner tubular body portion. The inner and outer tubular seats cooperatively define an internal space.
In use, biomass fuel is placed into the combustion chamber for generation of wood gas by pyrolysis. The wood gas flows out of the through holes into the internal space, flows upward together with air coming from the air inlets, and then flows back into the combustion chamber through the through holes which are located proximate to the seal portion for facilitating combustion.
Since the inner and outer tubular seats are typically made of metal, heat dissipation of the inner and outer tubular seats is relatively fast, which may decrease temperature of the wood gas in the internal space below a desirable ignition temperature. As such, the combustion performance is poor and the biomass fuel is not utilized effectively.
The conventional portable biomass stove may be provided with a fan unit so as to facilitate air flow into the internal space. However, without means for properly guiding the direction of the air flow, the air may not be able to mix efficiently with the wood gas for achieving a better combustion process.